Typewriting machine



Oct. 17, 1939. w. F. HELMOND 2,176,623

TYPEWRITING MACHINE Filed Jan. 9, 1957 2 Sheets-Sheet 1 A Y Inventor:

0a. 17, 1939. F, HELMOND 2,176,628

TYPEWRITING MACHINE Filed Jan. 9, 1937 2 Sheets-Sheet 2 fnevmfor; W

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Patented Oct. 17, 1939 UNITED STATES PATENT OFFIQE TYPEWRITING MACHINE Application January 9,

2 Claims.

This invention relates to spring-motors for letter-feeding the carriages of typewriting machines, and particularly to a motor arranged to permit ready removal or replacing of a carriagedriving spring. It is well known that a wide carriage machine requires a longer spring for satisfactory operation than an ordinary typewriter. Similarly, the addition of an attachment to a machine, such as a carriage extension for fanfold operation, or a tally roll supported by the carriage, increases the load requirements of a spring, and a stronger spring is indicated to prevent sluggish action of the carriage. One of the objects of this invention is to arrange the motor to permit ready replacement of one spring by another without detaching the spring-barrel mounting unit from the machine.

To attain the object of the invention, a replacement spring is encased in a holder, which 2 may be attached as a unit to a revoluble support,

thereby to form a spring-barrel, without the danger of the spring becoming unwound, as frequently occurred when a new spring had to be inserted in a spring-barrel. Novel means attaches the inner end of the spring to the arbor of the barrel mounting.

The invention provides an inexpensive, efficient spring-barrel that may be conveniently removed or replaced on the machine without the use of special tools or special skill.

The invention has .a spring-holder detachably connected to a rotatable mounting on an arbor which is secured in a bracket affixed to the frame of the typewriter. A spiral spring coiled in the holder and having its outer end afiixed thereto,

' may be detachably anchored to the arbor, which is revoluble for the purpose of adjusting the tension of the spring.

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a rear elevation of a typewriter, showing the carriage, escapement, and the carriage-feed spring-barrel.

Figure 2 is a side elevation, partly in section, showing the location of the spring-barrel, and the method of removing the spring-holder from the machine.

Figure 3 is a plan view of the spring-barrel showing the carriage moved to the right.

Figure 4 is a sectional rear elevation of the spring-barrel, illustrating tensioning and locking means.

Figure 5 is a section through the spring-barrel.

Figure 6 is a perspective view of the spring- 1937, Serial No. 119,744

barrel, illustrating the method of mounting the spring-holder.

Figure 7 is a view showing attachment of the spring to the arbor.

Figures 8, 9, and 10. are views showing difierent types of springs.

Figure 11 is a perspective view, showing a spring holder and dust-cover.

The carriage of a typewriting machine 2| is connected by a flexible strap or draw-band 22 to a spring-barrel 23, which is mounted upon the rear of the typewriter frame 25 by means of a bracket 24. The spring-barrel 23 tends to rotate clockwise of Figure 1 to pull the carriage against an escapement mechanism 26 having a gear 21 co-operating with a rack 28 on the carriage. The spring-barrel 23 comprises a removable draw-band drum 29, and a draw-band drum support 36. The draw-band drum 29 is a cupshaped casing" that covers the front of and encircles a coiled spring 3!, which is attached by means ofv a slot 66 at its outer end to a hook 32 on the inner wall of the holder, said spring 3| being permanently contained in said draw-band drum 29. A hook 33 to engage the strap 22 is provided on the outer periphery or rim of the draw-band drum 29 and the latter may have also a plurality of holes 34 around its rim toreceive screws 36 to secure it to the drum-support 30.

The drum-support is rotatably mounted upon an arbor 37, which is revolubly secured in a bracket 24, fastened to the rear portion of the typewriter frame by means of screws 39. The support 30 may be a pressed disk, having a rimportion Ml adapted to fit into the rim of the draw-band drum or spring-holder 29. Tapped holes 35 are provided on this rim-portion Ml, aligning with. the holes 34 in the spring-holder 29 when the spring-holder is mounted on the support, and the screws 36 are provided for fastening the holder and support together. An outwardly extending flange 4!, against which the rear edge of the holder 29 rests, may act as a guide for the strap 22. The drum-support 30 may be pressed mounted on a hub 62, having an interior V-groove 43 to co-operate with a bevelled flange M and a bevelled ring 45 to form a raceway for single row of bearing balls 45. A screw 41 tapped into the front end of the arbor 31 clamps a collar 48, and the bevelled ring 45 to the bevelled flange M formed on the arbor 3'! so that a firm bearing is aiforded for the balls. The collar 48 extends past the end of the arbor 31 and is provided with a hook 38 which engages in a slot 65 in the inner end of the spring 3| when the spring-holder 29 is mounted on the support 35. The spring 3! is wound or tensioned by rotating the arbor or spring anchor shaft 31, while the strap 22 holds the drum 23 in a stationary position.

The rear portion of the arbor 37 has a shoulder 49 which abuts against the front side of the bracket 2 to prevent endwise displacement in one direction. The head of a keeper-screw 50, which is threaded into the rear end of the arbor, prevents endwise displacement of the arbor in the opposite direction.

The arbor may be normally held against rotation by means of a worm-gear 5! formed on the arbor, said gear being smaller in diameter than the arbor, its teeth being concave or re-entrant in form. With this worm-gear co-operates a worm 52, formed upon a vertical stem or shaft 53, having at its lower end a finger-knob E l for turning the same, and thereby slowly rotating the arbor 3! with the collar 53, hook 38, and inner end of the spring M, to adjust the tension. thereof in either direction.

The worm 52 is capable of withdrawal from mesh with the worm-gear 5i so as to permit rapid rotation of the arbor 37, independently of said worm.

By placing a screwdriver in the slot 55 of the screw 50, the arbor may be turned to the right, and the worm-gear 5i thereon may thereby be caused to force downwardly the worm 52 from its normal engaged or effective position to the disengaged or inefiective position as indicated by the dotted out line of the finger-knob 54, Figure l. Thereupon the continued turning of the screwdriver will cause the arbor to rotate, so that the spring may be wound to the desired tension. If the screwdriver is allowed to yield counter-clockwise of Figure 4, a restoring-spring 56 will lift the worm 52 and the shaft 53 from the ineffective position into eifective engagement with the worm-gear, which eventually reaches the normal arbor-locking position at Figure 4. In turning the arbor clockwise of Figure 4, the spring 5t yields so that the slidable worm 52 acts as a spring-pressed pawl to permit free rotation of the arbor clockwise, but checking its rotation in the opposite direction. Said spring 56 bears up against the head of a screw 57 threaded into a hole formed in the top of the Worm-shaft 53, and rests on the bottom of a counterbored hole 53 which forms a stop for limiting the downward movement of the worm-shaft. The spring normally holds a shoulder 59 on the worm-shaft up against the bottom of the bracket 2%, which forms a stop. The shaft 53 is rotatably and slidably guided by a lower end portion 69 in a hole 6! counterbored in the bottom of the bracket 24, and by the shaft 53 in a bearing-hole 62.

These stops (formed by the lower end of the bracket and by the bottom of the counterbore 58) constitute means for limiting the axial movement of the worm between two positions.

The worm-shaft may be locked against rotation by means of a set screw 53, threaded into the bracket and bearing against the lower portion Bil of the worm-shaft.

In Figure 5 a narrow carriage driving spring, suitable for a lightweight carriage is illustrated, while Figure 8 illustrates a wide spring for a heavy carriage. Similarly Figures 9 and 10 illustrate long and short springs for use with wide and narrow carriages respectively.

Figure 7 shows the construction of the inner end of the carriage-spring 3|. The spring holder 29 may be assembled on the support 30 in such a manner that initially the collar 48 and the protruding hook 38 clear the inner turn of the spring, as illustrated in Figure '7. Then, to engage and tension the carriage spring St, the arbor 31 is rotated clockwise of Figure 4. The hook 38 will thus contact the innermost turn of the spring until it reaches the slot 65, through which it will enter to catch the spring 3| so that further rotation of the arbor winds said spring 3i upon the collar 48. Preparatory toremoving the spring holder 29 and spring 3i, the arbor 31 may be rotated counter-clockwise of Figure 4 until the spring is relaxed, and further rotation will cause the hook 38 to strike the end of the slot 65 and the spring will rise on the chamfered portion 58 of the hook 38 and be released.

Figure 11 illustrates a cover or cap 64 for closing the spring-holder or drum 29. The cover is fitted as a cap over the open side of the holder to guard the spring 3! while the drum and spring are detached from the machine or spring-motor.

Figures 2 and 3 show how the spring-holder 29 is removed from a typewriter. The carriage is moved to the right, and the spring is untensed, as described. When the strap 22 and screws 36 have been removed, the spring-holder 29 is free to be moved into the position indicated by the dot-and-dash lines of Figure 3, from whence it may be lowered, as shown in Figure 2 and rearwardly removed from the machine.

To permit rapid rotation of the arbor when desired the worm-shaft 53 is. movable endwise. By rotating the arbor clockwise, the worm-shaft 53 may be carried down endwise; and the worm 52 is so short that it may by these means be readily driven down to a position where it can clear the worm-wheel. Hence the latter may independently be forced around as far as desired, thereby tensioning the spring. This rapid adjustment of the arbor may be effected by any suitable tool, such as a screwdriver, as the arbor is provided at its rear end with a screw having a slotted head. Thus it is only necessary to place the screwdriver in the slot and rotate it to the right as far as desired: the first effect being to force the worm-shaft down from an eifective to an ineffective position, whereupon the winding of the spring by the screwdriver may be effected by continued turning of the screwdriver. If it is desired to unwind the spring rapidly, this can also be done by a screwdriver, first by turning it to the right to force down the worm and wormshaft (which may be held down by grasping the finger-knob 54 provided on the lower end thereof, thus keeping the worm out of contact with the worm-wheel) and then allowing the spring to unwind itself under control of the screwdriver. The finger-knob of the worm-shaft may then be released, so that the restoring-spring lifts the worm into re-engagement with the worm-gear. Said worm thus acts as a locking-dog or pawl for the worm-gear, at the same time being capable of effecting fine or slow adjustments of the arbor by rotating said hand-wheel. In using a screwdriver to rotate the arbor clockwise, to wind up the carriage-spring, it is not necessary to hold the worm out of mesh with the worm-gear, as the teeth of the worm-gear will click past the end of the spring-pressed worm, the worm and Worm-gear then acting like a pawl and ratchet.

When it is desired to remove and change a spring for any reason, the carriage is moved to the right, and a screwdriver is inserted in the screwslot in the rear end of the arbor, and rotated clockwise until the worm is displaced endwise out of contact with the worm-gear on the arbor. While the finger-knob 54 is held down by hand, the screwdriver controls the counter-clockwise rotation of the arbor which results from the spring unwinding itself. The strap may then be removed from the hook on the spring-barrel, and the screws 33 securing the spring-holder or drum 29 to the support 30 are removed. The springholder 29, containing the carriage-spring 3 l may then be removed by sliding it forward free of the support 39.

To replace a replacement spring, a suitable spring coiled in its individual holder or drum 29 is selected and slipped over the support 30. The screws 36 holding the support and holder are then inserted, the strap hooked over the hook on the holder, and the spring tensioned by rotating the arbor clockwise. Due to the construction of the inner end of the spring, the hook on the arbor will automatically engage a slot on the spring when the arbor is rotated clockwise.

The combined spring-holder and draw-band drum of my invention is inexpensive and is easily removed or replaced without special tools. Spring-holders having different types of springs may be available for replacement. The cover 59 may cap the spring-holder 29 to completely encase the spring during times that the holder 29 and its spring 3| are detached from the machine. The spring thus may come originally in a package formed by the draw-band drum itself and the cover 64, it being understood that the cover 64 is discarded upon installing the drum 29, and the therein-contained spring, in the spring motor. Such package 29, 64, containing the spring 3|, is

also conveniently carried in the service-mans parts kit.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typing machine, the combination with a carriage, of a spring-motor therefor including a coiled driving spring, a draw-band drum connected to be driven by, and permanently containing said spring, said drum adapted to be connected, as by means of a draw-band wound thereupon, to drive said carriage, a spring-anchoring shaft mounted on the machine frame, and a drum-support mounted to rotate relatively to said anchor shaft, said draw-band drum being detachably mounted on said rotatable support and the spring being detachably anchored to said shaft to permit removal or replacement of the draw-band drum, together with its contained spring, from or onto said support.

2. In a typing machine, the combination with a carriage, of a spring-motor therefor including a coiled driving spring, a draw-band drum connected to be driven by, and permanently containing said spring, said drum adapted tobe connected, as by means of a draw-band wound thereupon, to drive said carriage, a spring-anchoring shaft mounted on the machine frame, and a drum-support mounted to rotate relatively to said anchor shaft, said drum-support and dr'Lun each having a rim portion, the rim portions being detachably fitted and detachably secured to one another to permit removal or replacement of the drum, together With its contained spring, from or onto said support.

WILLIAM F. HELMOND. 

